Conventionally, when a printed-circuit board is bored by pulse oscillating laser, a current value S of drive current to be supplied to a laser oscillator, a frequency T of pulse oscillation, a pulse width W and pulse number N are set as working condition. The current value S, the frequency T of pulse oscillation, the pulse width W and the pulse number N are variously changed, and stored in a working condition file as working condition. The working condition file is stored and saved in a computer-readable storage medium, such as a magnetic tape, a floppy disk, a hard disk and a magneto-optic disk, each of them being connected to a control device of the laser working machine.
FIG. 5 shows an example of display showing a setting screen of a working condition setting device (not shown) in conventional laser working machine. A list 9 of the working condition file as shown in FIG. 5 is displayed on the setting screen of the working condition setting device (not shown). An operator of the laser working machine watches this list and operates a not shown input unit and inputs the working condition. In the example shown in FIG. 5, a first working condition for example is set to current value S1 frequency T1, pulse width W1 and pulse number N1, a second working condition is set to current value S2, frequency T2, pulse width W2 and pulse number N2, and a third working condition is set to current value S3, frequency T3, pulse width W3, and pulse number N3. In a fourth and subsequent working conditions also, current value S, frequency T, pulse width W and pulse number N are similarly set.
At the time of actual working, the control device reads out a working program from the storage medium or another computer-readable storage medium connected to the control device, and executes the program. The control device then reads out an appropriate working condition from the working condition file based on a working condition number (number in the column of “No.” of the list in FIG. 5) and a working mode, and supplies drive current of the current value S such that N-number of laser pulses having frequency T and pulse width W to the laser oscillator. The laser oscillator oscillates laser by the supplied drive current for working.
In this prior art, however, values of the current value S, frequency T, pulse width W and pulse number N can be input up to an upper limit predetermined in the working condition setting device of the laser working machine independently without being affected by other set value and therefor, there is an adverse possibility that a load acting on the laser oscillator exceeds a permissible load range depending upon a combination of the values of the current value S, frequency T, pulse width W and pulse number N.
Thus, in the prior art, the laser oscillator is operated beyond the permissible range of the load in some cases, or the laser oscillator is operated for a long time with a load which is within the permissible range but close to the upper limit in some cases, and there is a problem that parts constituting the laser oscillator are worn and deteriorated soon.
Further, when the working condition is newly set, in order to find out an appropriate working condition capable of working efficiently without applying excessive load to the laser oscillator, it is necessary to repeat working operation while variously changing the working condition and checking operation of balance between the load on the laser oscillator and the working efficiency. Therefore, there is a problem that extremely long time and enormous labor are required to finally determine the working condition.
The present invention has been accomplished to solve the above problems, and it is an object of the invention to provide a working condition control method of a laser working machine and a computer-readable storage medium storing a program for the method capable of easily setting a working condition of laser working such that a load acting on a laser oscillator stays in an appropriate range.